Animal facilities in the Biomedical Science Tower (BST) and the South Biomedical Science Tower (S-BST) at the University of Pittsburgh house an average daily census of more than 61,000 rodents in support of more than 113 PHS-funded biomedical and behavioral research projects. This represents an investment by the PHS of more than $25 million in annual direct costs. Of that amount, $7.1 million in annual direct costs supports research that uses rats housed in the BST and S-BST. Protection of these rodent colonies from communicable diseases is crucial to ensuring the continued success and productivity of the animal-based research programs at the University of Pittsburgh. Thus, the specific aim of this application for funding is: To obtain funds to purchase ventilated micro-isolator caging systems and HEPA-filtered laminar flow animal transfer stations for rat colonies housed in the South Biomedical Science Tower at the University of Pittsburgh. This specific aim is proposed to enhance the overall health status of rat colonies at the University of Pittsburgh through communicable disease prevention and through biocontainment in the event of an infectious disease outbreak.